Goodwill and Acquired Intangible Assets - Schedule of Goodwill (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2015 USD ($)
Schedule of Goodwill [Roll Forward]
Balance as of January 1, 2015	$ 1,051,294
Foreign currency translation	1,849
Balance as of June 30, 2015	1,135,947
Xerocole, Inc. [Member]
Schedule of Goodwill [Roll Forward]
Acquisition of goodwill	12,859
Codemate A/S [Member]
Schedule of Goodwill [Roll Forward]
Acquisition of goodwill	$ 69,945